I'm not saying it can't or shouldn't be done, it's just one of those things that needs to be done right if it's going to be done at all.

There are steel traps that will capture the bullets and bullet fragments/spray to deal with that issue, and good ventilation that's planned out properly will go a long way towards dealing with the lead residue in the discharge smoke. For the smoke residue that does settle out onto exposed surfaces, you want to keep surfaces in the shooting area slick so they can be easily cleaned.

Another option is to go to airguns for your indoor practice. They eliminate the smoke of discharge and the lead residue that is contained in it. That means no special ventilation requirements and you don't have to worry about contamination settling onto exposed surfaces. You do still need to have a decent target trap that will catch and not splatter the pellets since they are lead.